/**
 * 返回当前时间戳
 * @returns {number}
 */
export function getTime() {
    return Math.floor(Date.now() / 1000);
}

export function formatDate(format, timestamp) {
    return date(format, timestamp);
}

/**
 * 日期格式化
 * @param format 一般的Y-m-d H:i:s
 * @param timestamp
 * @returns {*}
 */

export default function date(format, timestamp) {
    //var that = this;
    var jsdate, f;
    // Keep this here (works, but for code commented-out below for file size reasons)
    // var tal= [];

    var txt_words = [
        "Sun",
        "Mon",
        "Tues",
        "Wednes",
        "Thurs",
        "Fri",
        "Satur",
        "January",
        "February",
        "March",
        "April",
        "May",
        "June",
        "July",
        "August",
        "September",
        "October",
        "November",
        "December",
    ];
    // trailing backslash -> (dropped)
    // a backslash followed by any character (including backslash) -> the character
    // empty string -> empty string
    var formatChr = /\\?(.?)/gi;
    var formatChrCb = function (t, s) {
        return f[t] ? f[t]() : s;
    };
    var _pad = function (n, c) {
        n = String(n);
        while (n.length < c) {
            n = "0" + n;
        }
        return n;
    };
    f = {
        // Day
        d: function () {
            // Day of month w/leading 0; 01..31
            return _pad(f.j(), 2);
        },
        D: function () {
            // Shorthand day name; Mon...Sun
            return f.l().slice(0, 3);
        },
        j: function () {
            // Day of month; 1..31
            return jsdate.getDate();
        },
        l: function () {
            // Full day name; Monday...Sunday
            return txt_words[f.w()] + "day";
        },
        N: function () {
            // ISO-8601 day of week; 1[Mon]..7[Sun]
            return f.w() || 7;
        },
        S: function () {
            // Ordinal suffix for day of month; st, nd, rd, th
            var j = f.j();
            var i = j % 10;
            if (i <= 3 && parseInt((j % 100) / 10, 10) == 1) {
                i = 0;
            }
            return ["st", "nd", "rd"][i - 1] || "th";
        },
        w: function () {
            // Day of week; 0[Sun]..6[Sat]
            return jsdate.getDay();
        },
        z: function () {
            // Day of year; 0..365
            var a = new Date(f.Y(), f.n() - 1, f.j());
            var b = new Date(f.Y(), 0, 1);
            return Math.round((a - b) / 864e5);
        },

        // Week
        W: function () {
            // ISO-8601 week number
            var a = new Date(f.Y(), f.n() - 1, f.j() - f.N() + 3);
            var b = new Date(a.getFullYear(), 0, 4);
            return _pad(1 + Math.round((a - b) / 864e5 / 7), 2);
        },

        // Month
        F: function () {
            // Full month name; January...December
            return txt_words[6 + f.n()];
        },
        m: function () {
            // Month w/leading 0; 01...12
            return _pad(f.n(), 2);
        },
        M: function () {
            // Shorthand month name; Jan...Dec
            return f.F().slice(0, 3);
        },
        n: function () {
            // Month; 1...12
            return jsdate.getMonth() + 1;
        },
        t: function () {
            // Days in month; 28...31
            return new Date(f.Y(), f.n(), 0).getDate();
        },

        // Year
        L: function () {
            // Is leap year?; 0 or 1
            var j = f.Y();
            return ((j % 4 === 0) & (j % 100 !== 0)) | (j % 400 === 0);
        },
        o: function () {
            // ISO-8601 year
            var n = f.n();
            var W = f.W();
            var Y = f.Y();
            return Y + (n === 12 && W < 9 ? 1 : n === 1 && W > 9 ? -1 : 0);
        },
        Y: function () {
            // Full year; e.g. 1980...2010
            return jsdate.getFullYear();
        },
        y: function () {
            // Last two digits of year; 00...99
            return f.Y().toString().slice(-2);
        },

        // Time
        a: function () {
            // am or pm
            return jsdate.getHours() > 11 ? "pm" : "am";
        },
        A: function () {
            // AM or PM
            return f.a().toUpperCase();
        },
        B: function () {
            // Swatch Internet time; 000..999
            var H = jsdate.getUTCHours() * 36e2;
            // Hours
            var i = jsdate.getUTCMinutes() * 60;
            // Minutes
            // Seconds
            var s = jsdate.getUTCSeconds();
            return _pad(Math.floor((H + i + s + 36e2) / 86.4) % 1e3, 3);
        },
        g: function () {
            // 12-Hours; 1..12
            return f.G() % 12 || 12;
        },
        G: function () {
            // 24-Hours; 0..23
            return jsdate.getHours();
        },
        h: function () {
            // 12-Hours w/leading 0; 01..12
            return _pad(f.g(), 2);
        },
        H: function () {
            // 24-Hours w/leading 0; 00..23
            return _pad(f.G(), 2);
        },
        i: function () {
            // Minutes w/leading 0; 00..59
            return _pad(jsdate.getMinutes(), 2);
        },
        s: function () {
            // Seconds w/leading 0; 00..59
            return _pad(jsdate.getSeconds(), 2);
        },
        u: function () {
            // Microseconds; 000000-999000
            return _pad(jsdate.getMilliseconds() * 1000, 6);
        },

        // Timezone
        e: function () {
            // Timezone identifier; e.g. Atlantic/Azores, ...
            // The following works, but requires inclusion of the very large
            // timezone_abbreviations_list() function.
            /*              return that.date_default_timezone_get();
             */
            throw "Not supported (see source code of date() for timezone on how to add support)";
        },
        I: function () {
            // DST observed?; 0 or 1
            // Compares Jan 1 minus Jan 1 UTC to Jul 1 minus Jul 1 UTC.
            // If they are not equal, then DST is observed.
            var a = new Date(f.Y(), 0);
            // Jan 1
            var c = Date.UTC(f.Y(), 0);
            // Jan 1 UTC
            var b = new Date(f.Y(), 6);
            // Jul 1
            // Jul 1 UTC
            var d = Date.UTC(f.Y(), 6);
            return a - c !== b - d ? 1 : 0;
        },
        O: function () {
            // Difference to GMT in hour format; e.g. +0200
            var tzo = jsdate.getTimezoneOffset();
            var a = Math.abs(tzo);
            return (tzo > 0 ? "-" : "+") + _pad(Math.floor(a / 60) * 100 + (a % 60), 4);
        },
        P: function () {
            // Difference to GMT w/colon; e.g. +02:00
            var O = f.O();
            return O.substr(0, 3) + ":" + O.substr(3, 2);
        },
        T: function () {
            return "UTC";
        },
        Z: function () {
            // Timezone offset in seconds (-43200...50400)
            return -jsdate.getTimezoneOffset() * 60;
        },

        // Full Date/Time
        c: function () {
            // ISO-8601 date.
            return "Y-m-d\\TH:i:sP".replace(formatChr, formatChrCb);
        },
        r: function () {
            // RFC 2822
            return "D, d M Y H:i:s O".replace(formatChr, formatChrCb);
        },
        U: function () {
            // Seconds since UNIX epoch
            return (jsdate / 1000) | 0;
        },
    };

    var $date = function (format, timestamp) {
        //that = this;
        jsdate =
            timestamp === undefined
                ? new Date() // Not provided
                : timestamp instanceof Date
                ? new Date(timestamp) // JS Date()
                : new Date(Math.floor(timestamp) * 1000); // UNIX timestamp (auto-convert to int)
        return format.replace(formatChr, formatChrCb);
    };
    return $date(format, timestamp);
}
